Restore lost data without backup

It depends on what data?

• iCloud backup doesn’t include information already stored in iCloud, like Contacts, Calendars, Bookmarks, Mail, Notes, Voice Memos, shared photos, iCloud Photos*, Health data, call history, and files you store in iCloud Drive.

*-If you had turned on iCloud Photos, your content is automatically stored in iCloud. 

• Contacts are neither stored locally on an iPhone nor in SIM. They are synced to an email account that you had Google, iCloud, AOL, Exchange, Outlook, Yahoo or any Other
• Calendars, bookmarks, or contacts --> If you accidentally deleted your calendars, bookmarks, or ...
• Data stored in Cloud Drives (iCloud Drive, Google Drive, OneDrive, DropBox, Flickr, box, AmazonDrive, Adobe Creative Cloud etc)
• Notes that were with email client server --> Check your email accounts. Because many of the accounts have notes synced like Google, iCloud, AOL, Exchange, Outlook, Yahoo etc.